/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Microsoft.Extensions.Logging;
using Quartz;
using Quartz.Spi;

namespace Spring.Scheduling.Quartz;

/// <summary>
/// Quartz ThreadPool adapter that delegates to a Spring-managed
/// TaskExecutor instance, specified on SchedulerFactoryObject.
/// </summary>
/// <author>Juergen Hoeller</author>
/// <seealso cref="SchedulerFactoryObject.TaskExecutor" />
public class LocalTaskExecutorThreadPool : IThreadPool
{
    private ITaskExecutor taskExecutor;

    /// <summary>
    /// Initializes a new instance of the <see cref="LocalTaskExecutorThreadPool"/> class.
    /// </summary>
    public LocalTaskExecutorThreadPool()
    {
        Logger = LogManager.GetLogger(GetType());
    }

    /// <summary>
    /// Logger instance.
    /// </summary>
    protected ILogger Logger { get; }

    /// <inheritdoc />
    public virtual int PoolSize => -1;

    /// <inheritdoc />
    public string InstanceId
    {
        set { }
    }

    /// <inheritdoc />
    public string InstanceName
    {
        set { }
    }

    /// <inheritdoc />
    public virtual void Initialize()
    {
        // Absolutely needs thread-bound TaskExecutor to Initialize.
        taskExecutor = SchedulerFactoryObject.ConfigTimeTaskExecutor;
        if (taskExecutor == null)
        {
            throw new SchedulerConfigException("No local TaskExecutor found for configuration - " +
                                               "'taskExecutor' property must be set on SchedulerFactoryObject");
        }
    }

    /// <inheritdoc />
    public virtual void Shutdown(bool waitForJobsToComplete)
    {
    }

    /// <inheritdoc />
    public virtual bool RunInThread(Func<Task> runnable)
    {
        if (runnable == null)
        {
            return false;
        }

        try
        {
            taskExecutor.Execute(() => runnable().ConfigureAwait(false).GetAwaiter().GetResult());
            return true;
        }
        catch (TaskRejectedException ex)
        {
            Logger.LogError(ex, "Task has been rejected by TaskExecutor");
            return false;
        }
    }

    /// <inheritdoc />
    public virtual int BlockForAvailableThreads()
    {
        // The present implementation always returns 1, making Quartz (1.6)
        // always schedule any tasks that it feels like scheduling.
        // This could be made smarter for specific TaskExecutors,
        // for example calling <code>getMaximumPoolSize() - getActiveCount()</code>
        // on a <code>java.util.concurrent.ThreadPoolExecutor</code>.
        return 1;
    }
}
